Conventionally, in an apparatus that handles a fluid such as a chemical and the like, a fluid apparatus unit structure has been developed that gathers together and integrates plural fluid apparatus components with the goal of reducing the footprint (i.e., the projective area in plan view), which is advantageous in reducing the size of an apparatus having a reduced component installation space, reducing the leak points, which is advantageous for the reliability of the apparatus and simplification of the maintenance, and reducing the dead volume, which enables the effective use of the fluid. Such a fluid apparatus unit structure is used, for example, for removing a chemical fluid as necessary while carrying out chemical fluid circulation and water circulation, and is structured such that various types of fluid components that serve as structural elements (for example, valves regulators, various types of sensors such as pressure sensors, and various types of switches such as pressure switches and the like) are gathered together onto a base member and integrated by connecting the components by pipes.
In a conventional valve body, generally, a structure in which several locations are tightened by using joining members such as screws and bolts and the like is used as an assembly structure that integrates the structural members of a partitioned body (for example, see Patent Document 1)